Polymerization of vinyl monomers employing liquid acyl sulfonyl peroxide formulations derived from solid acyl alkylsulfonyl peroxides

ABSTRACT

Storage stable liquid compositions are prepared from solid acyl alkylsulfonyl peroxides and polar or polarizable solvents or solvent mixtures. The compositions are liquid at 0° C to -40° C and are useful as free-radical initiators for polymerization of vinyl monomers.

This is a division, of application Ser. No. 596,115, filed July 15,1975, now U.S. Pat. No. 4,043,940.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to compositions prepared from solid acylalkylsulfonyl peroxides and polar or polarizable solvents or solventmixtures. These novel compositions are used as free-radical initiatorsfor vinyl monomer polymerization processes.

2. Description of Prior Art

Acyl sulfonyl peroxides such as acetyl cyclohexylsulfonyl peroxide(ACSP) have found increasing use in polymerization and copolymerizationof vinyl monomers such as vinyl chloride and vinyl acetate. Theseinitiators are especially useful for increasing the output ofpolyvinylchloride (PVC) reactors when used in combination with dialkylperoxydicarbonates. Normally, a vinyl chloride polymerization whichemploys only a dialkyl peroxydicarbonate suffers through an initialinduction period in which little PVC is produced. By using acyl sulfonylperoxides such as ACSP in combination with dialkyl peroxydicarbonates arapid polymerization occurs initially which then continues throughoutthe polymerization. This results in a shorter polymerization cycle, anincreased rate of production of PVC and greater production of PVC fromPVC reactors.

Although acyl sulfonyl peroxides are quite useful in vinyl chloridepolymerizations, they are shock sensitive in the pure form. Hence, theyhave to be diluted in some manner for safe handling. Acetylcyclohexylsulfonyl peroxide (ACSP) is currently the only acyl sulfonylperoxide on the market that is available in commercial quantities. SinceACSP in pure form is a shock sensitive solid (melting point, 33°-35° C),three dilutions of ACSP are commercially available; they are: a) a28-30% solution of ACSP in dimethyl phthalate (DMP), b) a 20% solutionin toluene, and c) a 65% wetted solid. All three formulations have oneor more detrimental properties.

The 29% solution of ACSP in DMP has a very narrow recommended storagetemperature range of -5° to -9° C. The upper temperature limit was setby thermal stability restrictions whereas the lower temperature limitwas set by phase stability restrictions, that is, solids formed attemperatures at or below -9° C. Therefore, the producer as well as theusers of this formulation are forced to maintain expensive storagefacilities that maintain the temperature between -5° and -9° C. Nowrecognized is a possible hazard associated with this formulation whenstored below -9° C. Unexpected decompositions are possible if thisformulation is stored at -15° to -30° C. Apparently, DMP (m.p., 2° C)can crystallize thus increasing the concentration of ACSP in thesupernatant liquid at -15° to -30° C. ACSP could then massively andrapidly crystallize from the supernatant liquid thus increasing thetemperature of the system to the melting point of ACSP (33° - 35° C)which is above the decomposition temperature of ACSP (18° C). A rapiddecomposition is then possible.

The 20% solution of ACSP in toluene contains 80% toluene. This highlevel of toluene would discourage use of this formulation for producingpolyvinyl chloride (PVC) which would be used in food applications. Inaddition, spillage of this formulation could be hazardous because of theevaporation of low boiling toluene (b.P., 108°-110° C), thus leaving ashock sensitive solid residue. Furthermore, this formulation issignificantly less stable than the 28-30% ACSP in DMP and readilydevelops color during storage.

The 65% wetted solid is not homogenous and is an extremely difficultformulation to handle. Because of the low thermal stability of ACSP, the65% wetted solid must be stored below 0° C resulting in a solid blockbecause of the water freezing. In this form it must be thawed orhazardously broken-up prior to use. Unlike the liquid formulations the65% wetted solid cannot be pumped into polymerization reactors.

In order to overcome the detrimental properties of the various ACSPformulations two liquid acyl alkylsulfonyl peroxides, acetylsecheptylsulfonyl peroxide and acetyl 1-methylcyclohexysulfonylperoxide, were offered for use. However, these peroxides are shocksensitive liquids and have only been offered as safe 50% liquidformulations in solvents such as DMP and isobutyl isobutyrate. Theseformulations have not been found by the PVC industry as acceptablereplacements for the ACSP formulations with their faults.

U.S. Pat. Nos. 3,650,972, 3,466,255 and 3,340,243 disclose prior artacyl sulfonyl peroxide formulations.

SUMMARY OF THE INVENTION

This invention concerns:

A) A liquid solution composition which is a safe storable stable liquidat 0° to -40° C consisting essentially of:

a. 10 to 70% by weight of a solid acyl alkylsulfonyl peroxide with amelting point of -10° to about 70° C having the formula ##STR1## where

(1) R₁ is an alkyl of 1 to 4 carbons

and

(2) R₂ is selected from the group consisting of an alkyl ormonochloroalkyl radical of 3 to 18 carbons and a cycloalkyl orclyclomonochloroalkyl radical of 4 to 12 carbons; and

b. 90 to 30% of a polar or polarizable solvent or solvent system havinga complete solidification temperature below about -10° C and amiscibility number greater than 8 and less than 21. This solvent orsolvent system has at least about 20% by weight based on the solid acylsulfonyl peroxide of a solvent which has a boiling point of at least165° C at 760 torr. (Note that 1 torr is equal to 1 mm of mercury ofpressure.)

The term "complete solidification temperatures" is defined as thetemperatures below which a liquid phase is absent and above which aliquid phase is present. It corresponds to the melting point when a puresolvent is employed. A polar solvent is defined as a solvent which hasat least one polar bond in its structure, that is, a bond createdbetween two atoms with different electronegativities, bonds such asC--O, C--N, C--Cl, O--H, N--O, etc. Carbon tetrachloride can beconsidered as a polar solvent under this definition even though it doesnot possess a dipole moment. A polarizable solvent is one which has pi(π) electrons which can be distorted (polarized) by a polar solute suchas a solid acyl alkylsulfonyl peroxide. Hence, an attractive interactionoccurs between the polarizable solvent and the polar solute which thenleads to dissolution of the solute. It is this interaction which allowsbenzene to solvate polar compounds. Certain solvents can be both polarand polarizable solvents.

B) Processes using the novel improved liquid acyl alkylsulfonyl peroxideformulations described above as initiators for polymerizingethylenically unsaturated monomers, such as, vinyl chloride, vinylacetate and methyl methacrylate, which monomers are responsive atsuitable temperatures to initiating amounts of these liquidformulations.

DETAILED DESCRIPTION OF THE INVENTION

It has now been surprisingly found that improved liquid ACSPformulations with wider storage temperature ranges and, optionally,higher ACSP levels can be obtained when certain polar or polarizablesolvents or polar or polarizable solvent mixtures are employed in theseformulations.

    ______________________________________                                        Examples:                                                                     Formu-             Sol-      (Cosolvent)                                      lation   ACSP, %   vent, %   Second Solvent, %                                ______________________________________                                        I        30        DMP, 55    DEP.sup.1, 15                                   II       35        DMP, 51    DEP, 14                                         III      40        DMP, 47    DEP, 13                                         IV       30        DMP, 55   4-Butyrolactone, 15                              V        30        CH.sub.2 Cl.sub.2, 56                                                                    DMP, 14                                         VI       30        CH.sub.2 Cl.sub.2, 56                                                                   4-Butyrolactone, 14                              VII      30        DMP, 35   Ethyl acetate, 35                                VIII     30        4-Butyro- None                                                                lactone, 70                                                ______________________________________                                         .sup.1 DEP is diethyl phthalate.                                         

These compositions are shock stable, are thermally stable at 0° to -10°C and remain homogeneous liquids at 0° to -40° C whereas the prior artcompositions of 30% ACSP in DMP (similar to the commercial 28-30% ACSPformulation) and 30% ACSP in DEP solidify significantly above -40° C.The improved liquid ACSP formulations have also been found to be asefficient in vinyl chloride (VCl) suspension polymerizations as thecommercial ACSP formulations and, because of their widened storage andhandling temperature range, they have been found to be more easilyhandled during the initial stages of the VCl polymerization processesthan the commercial ACSP formulations. In addition, most of the improved30% or higher ACSP liquid formulations of this invention were found tohave lower viscosities than the commercial 28-30% ACSP/DMP liquidformulation. Lower viscosity is an important initiator property sincepumping of the initiator is, therefore, easier and initiator containersare more quickly and more completely emptied.

It should be emphasized that the acyl sulfonyl peroxides (1) utilized inthe compositions of this invention are solids (m.p., above -10° C).Illustrative solid acyl alkylsulfonyl peroxides (1) which come under thedefinition of (1) are: acetyl t-amylsulfonyl peroxide (m.p., about 5°C), acetyl t-butylsulfonyl peroxide (m.p., 35°-37° C), acetyl3-chloro-1-methylpropylsulfonyl peroxide (m.p., 32°-33° C) and ACSP(m.p., 33°-35° C).

The compositions of this invention include, in addition to the solidacyl alkylsulfonyl peroxide (1), a polar or polarizable liquid solventor a polar or polarizable solvent mixture. The solvent or solventmixture must have sufficient attraction for the solid acyl alkylsulfonylperoxide such that the compositions of this invention will exhibit nosolid formation or phase separation at temperatures of about 0° to -40°C, which includes the ordinary storage temperature used in industry forstorage of acyl alkylsulfonyl peroxides. A measure of the attraction ofsolid acyl alkylsulfonyl peroxide and solvent or solvent mixture foreach other was described in the June 1972 edition of Chemical Technology(pages 359-363) by N. B. Godfrey. Godfrey introduced the concept ofsolvent selection by miscibility number (M) and listed the M numbers forapproximately 400 organic liquids. The higher the M number the higherthe lipophilic (affinity for oil-like substances) character of theorganic liquid. Normally, two liquids which have M numbers which differby less than 15 units are miscible in all proportions at 25° C.Occasionally this relationship broke down, i.e., the M number range wasless than 31. Therefore, Godfrey gave these solvents dual M numbers. Thelower M number was used for predicting miscibility of the selectedsolvent with more lipophilic solvents whereas the higher M number wasused for predicting miscibility of the selected solvent with lesslipophilic solvents. For instance, adiponitrile has the dual M numbers 8and 19. At 25° C adiponitrile will be completely miscible with solventshaving M numbers between 23 (i.e., 8+15) and 4 (i.e., 19-15).

Based on the M numbers listed by Godfrey for sulfonyl compounds acylalkylsulfonyl peroxides have been assigned the dual M numbers 12 and 17.At 25° C normally liquid acyl alkylsulfonyl peroxides will be completelymiscible with high lipophilic solvents with M numbers up to 27 (i.e.,12+15) and with low lipophilic solvents having M numbers down to about 2(17-15). However, because of strong hydrogen-bonding interactions of thelower glycols, the liquid acyl alkylsulfonyl peroxides display anomalousmiscibility behavior with the lower glycols (M numbers of 2-4) and arenot miscible in all proportions at 25° C.

The compositions of this invention, however, deal with improved liquidacyl alkylsulfonyl peroxide formulations which are derived from solid(m.p., between -10° and 70° C) rather than liquid acyl alkylsulfonylperoxides. In addition, this invention deals with the miscibility ofsolvent or solvent systems and solid acyl alkylsulfonyl peroxides at 0°C or lower rather than at 25° C. In general it has been found thatsolvents or solvent mixtures which have M numbers differing by less than9 units from those of the acyl alkylsulfonyl peroxides (12, 17) willproduce stable liquid acyl alkylsulfonyl peroxide solutions whichcontain 10% to 70%, preferably 25% to 60%, of solid acyl alkylsulfonylperoxide at 0° to -40° C. Therefore, solvents or solvent mixtures whichare in the M number range of greater than 8 and less than 21 willgenerally exhibit sufficient solvation power to produce liquid acylalkylsulfonyl peroxide compositions at 0° to -40° C which contain 10 to70%, preferably 25 to 60%, of solid (m.p., between -10° C and 70° C)acyl alkylsulfonyl peroxide.

Solvents having M numbers outside the range of greater than 8 and lessthan 21 have been found to be poor solvents for solid acyl alkylsulfonylperoxides at 0° to -40° C because of the low solubility of solid acylalkylsulfonyl peroxides in these solvents. For instance, dioctylphthalate (M number =24), cyclohexane (M number =28), isobutylisobutyrate (M number = 23) and ethylene glycol (M number = 2) were poorsolvents for ACSP.

In addition to the M number requirement, the useful solvent or solventsystem should have a complete solidification temperature below about-10° C. The complete solidification temperature of a pure solventcorresponds to the melting point of that solvent whereas the completesolidification temperature of a solvent mixture corresponds to thetemperature below which a liquid phase is absent and above which aliquid phase is present in the solvent mixture. The completesolidification temperature of a solvent system will generally correspondto a temperature lower than the melting point of the pure solventcomponents. If the complete solidification temperature of the solvent orsolvent system is above -10° C, the liquid acyl alkylsulfonyl peroxideformulation which is made from a solid acyl alkylsulfonyl peroxide andthe solvent system will separate into phases (solid and liquid) or willsolidify when the composition is stored below about -20° C. Forinstance, it has been found that the commercial liquid ACSP formulation(28-30% ACSP/70-72% DMP) started to solidify after two weeks at -23° Cevent though DMP had M numbers of 12 and 19. The liquid above the solidactually increased in ACSP concentration (supersaturated at -23° C);hence, the solvent DMP (m.p., 2° C) came out of solution first. The samephenomenon occurred with a 30% ACSP/70% DEP formulation. Furthermore,when a 62/8 mixture of DMP/DEP, which had a complete solidificationtemperature of about -7° C, was used to produce a 30% ACSP/62 % DMP/8%DEP formulation, the formulation solidified at -45° C. A 55/15 mixtureof DMP/DEP, which had a complete solidification temperature below -28°C, produced a 30% ACSP/55% DMP/15% DEP formulation in which no solidformation or phase separation occurred after 20 weeks at -45° C.

In addition to the M number and the complete solidification temperaturerequirements for the solvents or solvent systems employed, sufficientsolvent with a boiling point above about 165° C at 760 torr should bepresent in order to suppress residue impact shock sensitivity. Forinstance, it has been found that 30% ACSP/70% CH₂ Cl₂ is phase stable(no solidification) after 17 weeks at -50° C. Since CH₂ Cl₂ has an Mnumber of 20 and a melting point of -97° C, it should be and is a goodsolvent for ACSP. However, its boiling point is only 40° C, thus, if the30% ACSP/70% CH₂ Cl₂ formulation is spilled CH₂ Cl₂ rapidly evaporatesleaving behind a nearly pure, shock sensitive ACSP residue. It has beenfound that this shock hazard is suppressed by incorporating in theformulation about 20% by weight, based on solid acyl alkylsulfonylperoxide, of a solvent which boils above about 165° C at 760 torr.

In restating the above-mentioned requirements of the invention, theinvention is directed to improved liquid acyl alkylsulfonyl peroxidecompositions which are storable liquids at 0° to -40° C. Thesecompositions should contain 10to 70% (preferably 25 to 60%) of a solidacyl alkylsulfonyl peroxide having the formula ##STR2## This peroxideshould have a melting point in the range of between -10° and 70° C. R₁is an alkyl of 1 to 4 carbons such as methyl, ethyl or butyl. R₂ is analkyl or chloroalkyl radical having 3 to 18 carbons, normally 3 to 8carbons with the most preferred range being 3 to 6 carbons, or acycloalkyl or cyclochloroalkyl radical of 4 to 12 carbons. Thechlorosubstituted alkyl and cycloalkyl groups are normallymono-substituted groups.

The compositions include 90 to 30% (preferably 75 to 40%) by weight of apolar or polarizable solvent or solvent system having a completesolidification temperature below -10° C and an M number of greater than8 and less than 21. The solvent or solvent system should possess atleast about 20% by weight based on solid acyl alkylsulfonyl peroxide ofa solvent or solvent system which boils above 165° C at 760 torr.

More than two polar or polarizable solvents can be used to produce theimproved liquid acyl alkylsulfonyl peroxide formulations of thisinvention as long as the criteria for boiling point, completesolidification temperature and M number are essentially met. Similarformulations using liquid acyl alkylsulfonyl peroxides can also be madeemploying similar solvents or solvent systems.

A list of polar or polarizable solvents according to class of compoundand coming within the broad scope is given hereinafter for purpose ofillustration and not as any limitation on the scope of the invention.

POLAR SOLVENTS

(a) Haloaromatic hydrocarbons and nitroaromatic hydrocarbons, such as,monochlorobenzene, dichlorbenzene, nitrobenzene and chlorotoluene.

(b) Polyhaloalkanes and polyhaloalkenes, such as, carbon tetrachloride,trichloroethane, methylene chloride, ethylene dichloride,trichloroethylene, perchloroethylene and propylene dichloride.

(c) Alkyl cyanides having 2-4 carbon atoms, such as, acetonitrile,propionitrile and butyronitrile. Aryl nitriles such as benzonitrile.

(d) Dialkyl ethers and heterocyclic ethers having only carbon and oxygenin the ring, such as, diethyl ether, ethyl isopropyl ether, dibutylether, furan, tetrahydrofuran and dioxane.

(e) Lower alkanols and lower alkoxyalkanols (ether alcohols), such as,methanol, ethanol, isopropanol, sec-butanol, methoxybutyl alcohol andtetrahydrofurfuryl alcohol.

(f) Lower alkanones and cycloalkanones, such as, acetone, methyl ethylketone, dibutyl ketone, pentanone, cyclohexanone,trimethyldihydroisophorone, and diacetone alcohol.

(g) Alkyl esters of alkanoic acids, alkanedioic acids, alkanetrioicacids, alkenoic acids, ketoacids, alkenedioic acids, cycloalkanoicacids, aryl carboxylic acids and aryl dicarboxylic acids, such as,methyl acetate, ethyl acetate, butyl acetate, amyl acetate, octylacetate, isobutyl isobutyrate, butyl propionate, ethyl acetoacetate,dioctyl adipate, didecyl adipate, diethyl carbonate, diethyl maleate,dibutyl maleate, dibutyl sebacate, diisobutyl adipate, dioctyl azelate,ethyl lactate, butyl lactate, triethyl citrate, tributyl citrate,dimethyl phthalate, diethyl phthalate, dibutyl phthalate,di(methoxyethyl) phthalate, ethyl methyl phthalate, isopropyl methylphthalate and mixed alkyl phthalate esters made from mixtures ofalcohols having 7, 9 and 11 carbons or from mixtures of alcohols having6, 8 and 10 carbons.

(h) Cyclic esters such as 3-butyrolactone, 4-butyrolactone and propylenecarbonate.

(i) Carboxylate esters of alkanediols such as the mono- and thediisobutyrate esters of 2,2,4-trimethyl-1,3-pentanediol, ethylene glycoldiacetate, ethylene glycol mono butyl ether acetate, diethylene glycolmono butyl ether acetate, diethylene glycol mono ethyl ether acetate andethylene glycol mono ethyl ether acetate.

(j) Trialkyl phosphates, tri(alkoxyalkyl) phosphates, triarylphosphates, triaralkyl phosphates and halogenated trialkyl andtriaralkyl phosphates such as trimethyl phosphate, triethyl phosphate,tributyl phosphate, tri(butoxyethyl) phosphate, tricresyl phosphate,tri-(2-chloroethyl) phosphate and tri-(2,3-dibromopropyl) phosphate.

(k) Amides derived from carboxylic acids or phosphoric acids such asN,-N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidoneand hexamethylphosphoramide.

POLARIZABLE SOLVENTS

Aromatic hydrocarbons, haloaromatic hydrocarbons and nitroaromatichydrocarbons, such as:

benzene

toluene

ethylbenzene

cumene

xylene

α-methylstyrene

monochlorobenzene

chlorotoluene

dichlorobenzene

nitrobenzene

methylnaphthalenes

Several of the above are also polar solvents.

Table I summarizes M numbers, boiling points, melting points and watersolubilities of various polar or polarizable solvents which wereemployed in the practice of this invention.

                                      Table I                                     __________________________________________________________________________    M Numbers, Boiling Points, Melting Points                                     and Water Solubilities of Various Polar and Polarizable Solvents                            Godfrey.sup.1.                                                                      Boiling Point.sup.2.                                                                  Melting Point                                                                        Solvent 3.                                 Solvent       M Number                                                                            (B.P.), ° C                                                                    (M.P.), ° C                                                                   Water Solubility                           __________________________________________________________________________    Dimethyl phthalate (DMP)                                                                    12,19 283     2      Insol.                                     Diethyl phthalate (DEP)                                                                     13,20 295     -0.3   Insol.                                     Ethyl methyl phthalate                                                                      (est.)12,20                                                                         >283    --     Insol.                                     Dibutyl phthalate (DBP)                                                                       22  325     -35    Insol.                                     Triethyl citrate                                                                            (est.)16                                                                            294     --     Insol.                                     Butyl lactate (est.)15                                                                            188     -43    Insol.                                     Ethyl lactate   14  154     -25    Soluble                                    Dioctyl adipate                                                                             (est.)21                                                                            224(10) <-70   Insol.                                     Dibutyl maleate                                                                               22  225     --     Insol.                                     Isobutyl isobutyrate                                                                          23  149     -81    Insol.                                     Texanol.sup.4.                                                                              (est.)17                                                                            180(125)                                                                              -50    Insol.                                     2-Ethylhexyl acetate                                                                        (est.)22                                                                            198.5   -93    Insol.                                     n-Butyl acetate                                                                               22  125     -78    Insol.                                     4-Butyrolactone                                                                               10  204     -45    Soluble                                    Ethyl acetoacetate                                                                          13,19 181     -43    Soluble                                    Diacetone alcohol                                                                             14  169     -43    Soluble                                    Diisobutyl ketone                                                                             23  163-173 -46    Insol.                                     Tetrahydrofurfuryl alcohol                                                                    13  178     - 80   Soluble                                    N,N-Dimethylacetamide                                                                         13  164-166 -20    Soluble                                    N-Methyl-2-pyrrolidone                                                                        13  202     -24.4  Soluble                                    Tetramethylurea                                                                               15  177     -1     Soluble                                    Hexamethylphosphoramide                                                                       15  230-232(740)                                                                          6-8    Soluble                                    Phosflex 500.sup.5.                                                                         (est.)22                                                                            >200    <-76   Insol.                                     Tricresyl phosphate (TCP)                                                                     21  260-275(10)                                                                           <-35   Insol.                                     CH.sub.2 C1.sub.2                                                                             20  40      -97    Insol.                                     Acetone       15,17 56.5    -95    Soluble                                    Ethyl acetate   19  77      -84    Insol.                                     Acetonitrile  11,17 80      -45    Soluble                                    Toluene         23  111     -95    Insol.                                     Propylene carbonate                                                                         9,17  242.1   -73.1  Soluble                                    __________________________________________________________________________     Footnotes:                                                                    .sup.1. N. B. Godfrey, Chemical Technology, June 1972, 353-363. Est.          values are estimated from values listed for similar compounds.                .sup.2. Numbers in parentheses are pressure values in units of torr.          .sup.3. Soluble if greater than 10%, Insol. if less than 10%.                 .sup. 4. Texanol - The monoisobutyrate of 2,4,4-trimethyl-1,3-pentanediol     manufactured by Eastman Kodak Company.                                        .sup.5. Phosflex 500 - A chlorinated triaralkyl phosphate manufactured by     the Stauffer Chemical Company.                                           

Typical improved liquid acyl sulfonyl formulations which are derivedfrom solid acyl alkylsulfonyl peroxides and various polar or polarizablesolvents or solvent systems having M numbers in the range of greaterthan 8 and less than 21 are summarized in Table II. It should beemphasized that Table II does not exhaustively list of the possibleattractive liquid acyl alkylsulfonyl peroxide formulations of thisinvention. Other liquid acyl alkylsulfonyl peroxide formulations whichare derived from solid acyl alkylsulfonyl peroxides and polar orpolarizable solvents or solvent mixtures are possible which similarlyhave improved storage temperature ranges, safety and handlingcharacteristics when compared to the commercial liquid ACSPformulations. It should also be noted that several of the compositionsof this invention (TABLE II) employ more than two solvents.

The M numbers listed in Table II for single solvents were taken from orwere estimated from the data in the Godfrey reference mentioned above. Aweighted average of M numbers was employed when two or more solventswere employed. If a solvent pair both had dual M numbers weightedaverages of the higher numbers and of the lower numbers were calculatedto give dual M numbers for the solvent mixture. If a solvent pairconsisted of a solvent with a single M number and a solvent with dual Mnumbers, dual M numbers for the solvent mixture were calculated usingweighted averages of the single M number of one solvent with the upperand lower M numbers of the other solvent.

                                      Table II                                    __________________________________________________________________________    Improved Liquid Acyl Alkylsulfonyl Peroxide Formulations                      Derived from Solid Acyl Alkylsulfonyl Peroxides                               Comp-                                                                         osition                                                                           Peroxide, %                                                                           Solvent, %   Second Solvent, %                                                                            M Number                              __________________________________________________________________________    A   ACSP, 30                                                                              DMP, 60      DEP, 10        12.1,19.1                             B   ACSP, 30                                                                              DMP, 55      DEP, 15        12.2,19.2                             C   ACSP, 30                                                                              DMP, 45      DEP, 25        12.4,19.4                             D   ACSP, 30                                                                              DMP, 35      DEP,35         12.5,19.5                             E   ACSP, 30                                                                              DMP, 25      DEP, 45        12.6,19.6                             F   ACSP, 35                                                                              DMP, 51      DEP, 14        12.2,19.2                             G   ACSP, 40                                                                              DMP, 47      DEP, 13        12.2,19.2                             H   ACSP, 45                                                                              DMP, 43      DEP, 12        12.2,19.2                             I   ACSP, 40                                                                              DMP, 30      DEP, 30        12.5,19.5                             J   ACSP, 30                                                                              DMP, 55      Diacetone alcohol, 15                                                                        12.4,17.9                             K   ACSP, 30                                                                              DMP, 55      Tetrahydrofurfuryl alcohol, 15                                                               12.2,17.7                             L   ACSP, 30                                                                              DMP, 55      Ethyl acetoacetate, 15                                                                       12.2,19.0                             M   ACSP, 30                                                                              DMP, 55      Tetramethylurea, 15                                                                          12.6,18.1                             N   ACSP, 30                                                                              DMP, 55      Hexamethylphosphoramide, 15                                                                  12.6,18.1                             O   ACSP, 30                                                                              DMP, 55      Dimethylacetamide, 15                                                                        12.2,17.7                             P   ACSP, 30                                                                              DMP, 55      N-Methyl-2-pyrrolidone, 15                                                                   12.2,17.7                             Q   ACSP, 30                                                                              DMP, 55      Triethyl citrate, 15                                                                         12.9,18.4                             R   ACSP, 30                                                                              DMP, 55      Butyl lactate, 15                                                                            12.6,18.1                             S   ACSP, 30                                                                              DMP, 55      Dioctyl adipate, 15                                                                          13.9,19.4                             T   ACSP, 30                                                                              DMP, 65      4-Butyrolactone, 5                                                                           11.9,18.4                             U   ACSP, 30                                                                              DMP, 60      4-Butyrolactone, 10                                                                          11.7,17.7                             V   ACSP, 30                                                                              DMP, 55      4-Butyrolactone, 15                                                                          11.6,17.1                             W   ACSP, 30                                                                              DMP, 35      4-Butyrolactone, 35                                                                          11.0,14.5                             X   ACSP, 30                                                                              DMP, 25      4-Butyrolactone, 45                                                                          10.7,13.2                             Y   ACSP, 35                                                                              DMP, 55      4-Butyrolactone, 10                                                                          11.7,17.6                             Z   ACSP, 35                                                                              DMP, 50      4-Butyrolactone, 15                                                                          11.5,16.9                             AA  ACSP, 40                                                                              DMP, 40      4-Butyrolactone, 20                                                                          11.3,16.0                             AB  ACSP, 30                                                                              4-Butyrolactone, 70                                                                        --             10                                    AC  ACSP, 40                                                                              4-Butyrolactone, 60                                                                        --             10                                    AD  ACSP, 50                                                                              4-Butyrolactone, 50                                                                        --             10                                    AE  ACSP, 70                                                                              4-Butyrolactone, 30                                                                        --             10                                    AF  ACSP, 30                                                                              DEP, 55      4-Butyrolactone, 15                                                                          12.4,17.9                             AG  ACSP, 30                                                                              DEP, 35      4-Butyrolactone, 35                                                                          11.5,15.0                             AH  ACSP, 40                                                                              DEP, 40      4-Butyrolactone, 20                                                                          12.0,16.7                             AI  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Butyl lactate, 14                                                                            19.0                                  AJ  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Triethyl citrate, 14                                                                         19.2                                  AK  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      DMP, 14        18.4,19.8                             AL  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Dibutyl phthalate, 14                                                                        20.4                                  AM  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      DEP, 14        18.6,20.0                             AN  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Phosflex 500.sup.1., 14                                                                      20.4                                  AO  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Tricresyl phosphate, 14                                                                      20.2                                  AP  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      Texanol.sup.2., 14                                                                           19.4                                  AQ  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 63                                                                      4-Butyrolactone, 7                                                                           19.0                                  AR  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 56                                                                      4-Butyrolactone, 14                                                                          18.0                                  AS  ACSP, 30                                                                              CH.sub.2 C1.sub.2, 40                                                                      4-Butyrolactone, 30                                                                          15.7                                  AT  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 30                                                                      4-Butyrolactone, 30                                                                          15.0                                  AU  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      4-Butyrolactone, 14                                                                          17.8                                  AV  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      4-Butyrolactone, 14                                                                          17.7                                  AW  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      DMP, 14        18.3,19.8                             AX  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      DMP, 14        18.1,19.8                             AY  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      DEP. 14        18.5,20.0                             AZ  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      DEP, 14        18.4,20.0                             BA  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      Dibutyl phthalate, 14                                                                        20.4                                  BB  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      Dibutyl phthalate, 14                                                                        20.5                                  BC  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      Triethyl citrate, 14                                                                         19.1                                  BD  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      Triethyl citrate, 14                                                                         19.1                                  BE  ACSP, 35                                                                              CH.sub.2 C1.sub.2, 51                                                                      Butyl lactate, 14                                                                            18.9                                  BF  ACSP, 40                                                                              CH.sub.2 C1.sub.2, 46                                                                      Butyl lactate, 14                                                                            18.8                                  BG  ACSP, 15                                                                              CH.sub.2 C1.sub.2, 60                                                                      4-Butyrolactone, 25                                                                          17.1                                  BH  ACSP, 15                                                                              CH.sub.2 C1.sub.2, 80                                                                      DMP, 5         19.5,19.9                             BI  ACSP, 10                                                                              CH.sub.2 Cl.sub.2, 85                                                                      DMP, 5         19.6,19.9                             BJ  ACSP, 10                                                                              CH.sub.2 Cl.sub.2, 80                                                                      4-Butyrolactone, 10                                                                          18.9                                  BK  ACSP, 35                                                                              CH.sub.2 Cl.sub.2, 51                                                                      Phosflex 500.sup.1., 14                                                                      20.4                                  BL  ACSP, 40                                                                              CH.sub.2 Cl.sub.2, 46                                                                      Phosflex 500.sup.1., 14                                                                      20.5                                  BM  ACSP, 30                                                                              CH.sub.2 Cl.sub.2, 35                                                                      DMP, 35        16.0,19.5                             BN  ACSP, 30                                                                              DMP, 35      Acetone, 35    13.5,18.0                             B0  ACSP, 30                                                                              DMP, 35      Ethyl acetate, 35                                                                            15.5,19.0                             BP  ATASP.sup.3., 30                                                                      DMP, 55      DEP, 15        12.2,19.2                             BQ  ATASP.sup.3., 30                                                                      DMP, 55      4-Butyrolactone, 15                                                                          11.6,17.1                             BR  ATBSP.sup.4., 30                                                                      DMP, 55      DEP, 15        12.2,19.2                             BS  ATBSP.sup.4., 30                                                                      DMP, 55      4-Butyrolactone, 15                                                                          11.6,17.1                             BT  ACMPSP.sup.5., 30                                                                     DMP, 55      DEP, 15        12.2,19.2                             BU  ACMPSP.sup.5., 30                                                                     DMP, 55      4-Butyrolactone, 15                                                                          11.6,17.1                             BV  ATASP.sup.3., 30                                                                      4-Butyrolactone, 70                                                                        --             10                                    BW  ATBSP.sup.4., 30                                                                      4-Butyrolactone, 70                                                                        --             10                                    BX  ACMPSP.sup.5., 30                                                                     4-Butyrolactone, 70                                                                        --             10                                    BY  ATASP.sup.3., 30                                                                      DMP, 35      DEP, 35        12.5,19.5                             BZ  ATASP.sup.3., 30                                                                      DMP, 52.5    4-Butyrolactone, 17.5                                                                        11.5,16.8                             CA  ATASP.sup.3., 40                                                                      DMP, 30      4-Butyrolactone, 30                                                                          11.0,14.5                             CB  ATASP.sup.3., 40                                                                      DMP, 30      DEP, 30        12.5,19.5                             CC  ATBSP.sup.4., 40                                                                      DMP, 30      4-Butyrolactone, 30                                                                          11.0,14.5                             CD  ATBSP.sup.4., 40                                                                      DMP, 30      DEP, 30        12.5,19.5                             CE  ACSP, 30                                                                              Ethyl methyl phthalate, 70                                                                 --             12,20                                 CF  ACSP, 40                                                                              Ethyl methyl phthalate, 60                                                                 --             12,20                                 CG  ATASP.sup.3., 30                                                                      Ethyl methyl phthalate, 70                                                                 --             12,20                                 CH  ATASP.sup.3., 40                                                                      Ethyl methyl phthalate, 60                                                                 --             12,20                                 CI  ATBSP.sup.4, 30                                                                       Ethyl methyl phthalate, 70                                                                 --             12,20                                 CJ  ATBSP.sup.4., 40                                                                      Ethyl methyl phthalate, 60                                                                 --             12,20                                 CK  ACSP, 32                                                                              Ethyl methyl phthalate, 34                                                                 DEP, 17 plus DMP, 17                                                                         12.3,19.8                             CL  ACSP, 30                                                                              4-Butyrolactone, 10                                                                        DEP, 30 plus DMP, 30                                                                         12.1,18.1                             CM  ACSP, 30                                                                              4-Butyrolactone, 20                                                                        DEP, 25 plus DMP, 25                                                                         11.8,16.8                             CN  ACSP, 40                                                                              4-Butyrolactone, 10                                                                        DEP, 25 plus DMP, 25                                                                         12.1,17.9                             CO  ACSP, 40                                                                              4-Butyrolactone, 20                                                                        DEP, 20 plus DMP, 20                                                                         11.7,16.3                             CP  ACSP, 30                                                                              Ethyl acetate, 56                                                                          DMP, 14        17.6,19.0                             CQ  ACSP, 30                                                                              Ethyl acetate, 56                                                                          DEP, 14        17.8,19.2                             CR  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Butyl lactate, 14                                                                            18.2                                  CS  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Triethyl citrate, 14                                                                         18.4                                  CT  ACSP, 30                                                                              Ethyl acetate, 56                                                                          4-Butyrolactone, 14                                                                          17.2                                  CU  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Dibutyl phthalate, 14                                                                        19.6                                  CV  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Phosflex 500.sup.1., 14                                                                      19.6                                  CW  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Tricresyl phosphate, 14                                                                      19.4                                  CX  ACSP, 30                                                                              Ethyl acetate, 56                                                                          Texanol.sup.2., 14                                                                           18.6                                  CY  ACSP, 40                                                                              Ethyl acetate, 46                                                                          4-Butyrolactone, 14                                                                          16.9                                  CZ  ACSP, 40                                                                              Ethyl acetate, 46                                                                          DMP, 14        17.4,19.0                             DA  ACSP, 40                                                                              Ethyl acetate, 46                                                                          DEP, 14        17.6,19.2                             DB  ACSP, 40                                                                              Ethyl acetate, 46                                                                          Triethyl citrate, 14                                                                         18.3                                  DC  ACSP, 30                                                                              DMP, 35      Acetonitrile, 35                                                                             11.5,18.0                             DD  ACSP, 30                                                                              Propylene carbonate, 70                                                                    --             9,17                                  DE  ATASP.sup.3., 30                                                                      Propylene carbonate, 70                                                                    --             9,17                                  DF  ACSP, 30                                                                              Toluene, 55  4-Butyrolactone, 15                                                                          20.2                                  DG  ACSP, 30                                                                              DMP, 55      Propylene carbonate, 15                                                                      11.4,18.6                             DH  ACSP, 30                                                                              DMP, 35      Propylene carbonate, 35                                                                      10.5,18.0                             DI  ACSP, 40                                                                              DMP, 30      Propylene carbonate, 30                                                                      10.5,18.0                             DJ  ACSP, 30                                                                              CH.sub.2 Cl.sub.2, 35                                                                      Propylene carbonate, 35                                                                      14.5,18.5                             DK  ACSP, 30                                                                              Ethyl acetate, 35                                                                          Propylene carbonate, 35                                                                      14.0,18.0                             DL  ACSP, 40                                                                              Propylene carbonate, 60                                                                    --             9,17                                  DM  ACSP, 30                                                                              DMP, 23.3    DEP, 23.3 plus EMP.sup.6 23.3                                                                12,20                                 __________________________________________________________________________     .sup.1. Phosflex 500 - A chlorinated triaralkyl phosphate, manufactured b     Stauffer Chemical Company.                                                    .sup.2. Texanol - The monoisobutyrate of 2,4,4-trimethyl-1,3-pentandiol,      manufactured by the Eastman Kodak Company.                                    .sup.3. ATASP - Acetyl t-amylsulfonyl peroxide.                               .sup.4. ATBSP - Acetyl t-butylsulfonyl peroxide.                              .sup.5. ACMPSP - Acetyl 3-chloro-1-methylpropylsulfonyl peroxide.             .sup.6. EMP - Ethyl methyl phthalate                                     

Table III summarized various unattractive liquid acyl alkylsulfonylperoxide formulations which are derived from solid acyl alkylsulfonylperoxides and which satisfy some but not all of the criteria for thenovel improved liquid acyl alkylsulfonyl peroxide formulations;therefore, they do not come under the definition of this invention. EAand EB satisfy M number and boiling point criteria but do not satisfythe complete solidification temperature criterion; hence, the phasestabilities of EA and EB are poor compared to the invention compositionsat low temperatures. Composition EA is similar to the current liquidACSP formulation (28-30% ACSP/70-72% DMP). Also failing the completesolidification temperature criterion are compositions EF, EJ and EK.Compositions EC, ED, EE, EF and EG fail the M number criterion whereascompositions EC, EF, EH and EI fail the boiling point criterion.

                  Table III                                                       ______________________________________                                        Unattractive Acyl Alkylsulfonyl Peroxide Formulations                         Derived from Solid Acyl Alkylsulfonyl Peroxides                               Com-                           C.S.T..sup.1.                                                                             M                                  posi- Peroxide,                       B.P.,                                                                              Num-                               tion  %         Solvent, % ° C                                                                        ° C                                                                           ber                                     ______________________________________                                        EA    ACSP, 30  DMP, 70        2      283  12,19                              EB    ACSP, 30  DEP, 70        -0.3   295  13,20                              EC    ACSP, 30  Isobutyl       -81    149  23                                                 isobutyrate,                                                                  70                                                            ED    ACSP, 30  DBP, 70        -35    325  22                                 EE    ACSP, 30  DBP, 35        -35    325                                                     Isobutyl       -81    149  22.5                                               isobutyrate,                                                                  35                                                            EF    ACSP, 30  Cyclohexane,   6.6    80.7 28                                                 70                                                            EG    ACSP, 30  Ethylene       -13    197  2                                                  glycol, 70                                                    EH    ACSP, 30  Methylene      -97    40   20                                                 chloride, 70                                                  EI    ACSP, 30  Ethyl          -84    77   19                                                 acetate, 70                                                   EJ    ATASP, 30 DMP, 70        2      283  12,19                              EK    ATASP, 30 DEP, 70        -0.3   295  13,20                              ______________________________________                                         .sup.1. C.S.T. - Complete Solidification Temperature                     

VINYL POLYMERIZATIONS

In the free-radical initiated polymerizations or copolymerizations ofethylenically unsaturated monomers at suitable temperatures (andpressures), the improved liquid acyl alkylsulfonyl peroxide compositionsof this invention are found to be effective initiators with respect toefficiency. Ethylenically unsaturated monomers include:

(1) olefins, such as ethylene, propylene, styrene, alphamethylstyrene,chlorostyrene, vinyltoluene, vinyl benzyl chloride, vinyl pyridine anddivinylbenzene;

(2) diolefins, such as 1,3-butadiene, isoprene and chloroprene;

(3) vinyl esters, such as vinyl acetate, vinyl propionate, vinyllaurate, vinyl benzoate and divinyl carbonate;

(4) unsaturated nitriles, such as acrylonitrile and methacrylonitrile

(5) acrylic acid, methacrylic acid and their esters and amides, such asmethyl, ethyl, n-butyl and 2-ethylhexyl acrylates and methacrylates, andacrylamide and methacrylamide; maleic anhydride;

(6) maleic and fumaric acids and their esters;

(7) vinyl halo and vinylidene halo compounds, such as, vinyl chloride,vinyl bromide, vinyl fluoride, vinylidene chloride and vinylidenefluoride;

(8) perhalo olefins, such as tetrafluoroethylene, hexafluoropropyleneand chlorotrifluoroethylene;

(9) vinyl ethers, such as methyl vinyl ether, ethyl vinyl ether andn-butyl vinyl ether;

(10) allyl esters, such as allyl acetate, allyl benzoate, diallylphthalate, allyl ethyl carbonate, triallyl phosphate, diallyl fumarate,diallyl carbonate, and oxydiethylene bis(allyl carbonate):

(11) acrolein;

(12) methyl vinyl ketone; and

(13) mixtures thereof.

Temperatures of 0° C to 80° C, preferably 30° C to 65° C, and pureperoxide levels of 0.0005% to 2.0%, preferably 0.01% to 1.0%, can beemployed in these polymerization or copolymerization processes.Polymerizations can be carried out in suspension, emulsion, bulk orsolution.

These improved liquid acyl alkylsulfonyl peroxide compositions can alsobe advantageously employed for rapid gellation of unsaturated polyesterresins without subsequent curing of the unsaturated polyester resins. Inaddition, the improved liquid acyl alkylsulfonyl peroxide compositionscan be employed as latent generators of acid. Therefore, they can beused to generate acid catalysts.

DESCRIPTION OF PREFERRED EMBODIMENTS

The following are the general procedures that can be employed for thepreparation of the compositions of this invention:

Procedure A

A neat, i.e., substantially pure, solid acyl alkylsulfonyl peroxide isblended with the liquid solvent or solvent system at about 0° C to about20° C using adequate cooling. A clear liquid formulation is readilyobtained. This is one method for producing liquid acyl alkylsulfonylperoxide formulations from solid acyl alkylsulfonyl peroxides and watersoluble solvents or water soluble solvent systems.

Because of the hazard of handling pure sulfonyl peroxides, the followingare safer procedures for producing these compositions:

Procedure B

The sulfoxidation of an alkane in the presence of a carboxylic anhydrideresults in the formation of an oily product mixture containing 50 to 60%of the acyl alkylsulfonyl peroxide. This oily product is then added towater at 10° C or lower in order to precipitate the solid acylalkylsulfonyl peroxide. This solid is then washed with water in order toremove impurities. The solid is then dissolved in a solvent or solventmixture, water is separated off and the solution is washed with water at0° to 10° C. The solution is then dried resulting in a clear solution.The composition can then be adjusted as desired by adding a solvent orsolvent mixture. Water insoluble solvents are usually employed in thisprocedure, although water soluble solvents can be added during or afterthe drying step.

Procedure B-1

A wetted solid acyl alkylsulfonyl peroxide which has been washed free ofimpurities is used in this procedure. To the wetted solid is added asolvent or solvent mixture. After solution occurs the water layer isseparated and the product is dried. After separation of the desiccant byfiltration a clear solution is obtained. This procedure can be used whentwo water insoluble solvents or when a water soluble and a waterinsoluble solvent are employed.

Procedure C

The same method as employed in Procedure B-1 is used in this procedureexcept that when a water soluble solvent is used in conjunction withwater insoluble solvent the water insoluble solvent is first added tothe wetted solid sulfonyl peroxide, water is separated off, anhydrousMgSO₄ is added and stirred, then the water soluble solvent is addedprior to filtration.

Procedure D

The same method as employed in Procedure C is used in this procedureexcept that a water soluble solvent or solvent system is added to theliquid product after separating the desicant by filtration.

Procedure E

The same method as employed in Procedure B is used in this procedureexcept that a low boiling water insoluble solvent such as methylenechloride or ethyl acetate is used to initially prepare a dried dilutesolution of the solid acyl alkylsulfonyl peroxide. Then the desiredsolvent or solvent system is added and the initially employed lowboiling solvent is partially or completely removed in vacuo at 0° C to20° C, thus leaving a clear liquid. This procedure is a safe method forproducing improved liquid acyl alkylsulfonyl peroxide formulations fromsolid acyl alkylsulfonyl peroxides and water soluble solvents andsolvent mixtures.

Procedure F

The same as Procedure B except that a solution of 40-60% solid acylalkylsulfonyl peroxide in a low boiling water insoluble solvent isinitially prepared. Then the composition is adjusted by adding anothersolvent or solvent mixture and additional low boiling solvent, ifnecessary.

EVALUATION OF COMPOSITIONS

The various compositions were evaluated by these criteria: The physicalstate of the composition at 0° C and lower. The sensitivity of thecomposition to impact shock. The so-called Pressure Vessel Test. Loss ofassay, i.e., decrease in peroxy oxygen content, on storage in a closedcontainer at constant temperature. The rapid heat test temperature andthe burning character of these formulations were also evaluated.Pressure vessel test (PVT): The tester consisted of a cylindrical steelvessel (235 cc. volume) with a variable aperture disc in the side wall,closed at the top with a rupture disc. An aluminum rupture disc, crownedin shape, prestressed to 90% of its burst strength and rated at 98-100p.s.i.g. was used. There are 74 discs varying in an exponentialprogression from 1 mm. to 24 mm.

On rapidly heating a material in the tester, the disc bursts or remainsintact, depending on the force developed by the decomposition and theamount of venting supplied by the bore in the particular aperture discused. The bore size of the disc needed to prevent disc rupture is ameasure of the violence of the decomposition and the amount of gasgenerated.

It was determined that a 5.0 g. sample gave reproducible results; thesecould be used for comparative purposes. Because it is a well-known,widely used, and well-tested material, benzoyl peroxide (98% purity) wastested to provide a base line; the rupture disc burst at 14.9 mm. ventaperture.

Impact shock sensitivity test (ISST). -A modified Du Pont impact testingapparatus was used. In these tests a 5.0 kilogram weight was dropped onthe sample a measured distance to determine impact shock sensitivity.Sensitivity to impact shock is shown by noise (report), smoke, or byobvious decomposition of the sample. The maximum drop of the apparatuswas 36 inches.

Loss of assay. - In this test, a sample of the peroxide was placed in aclosed glass bottle and held in a constant temperature container for 4weeks. Then the peroxide was analyzed (assayed) for peroxy oxygencontent. The arithmetic difference between the original assay of of thesample and the final assay of the sample multiplied by 100% and dividedby the original assay of the sample is reported as % of assay lost.

The rapid heat test temperature was determined by placing one gram ofthe composition in a 15 mm. × 150 mm. test tube and heating the contentsat a rate of 1° C/min. until the composition vigorously decomposed. Thetemperature at which this occurred was the rapid heat temperature.

The burning character of the formulation was determined by placing 5 g.of liquid composition in a small aluminum pan (45 mm. wide, 12.5 mm.deep) and touching the liquid formulation with a flame. The timerequired for ignition, the time of active burning, the time ofnon-peroxidic burning (other burning) and the maximum flame height werenoted.

Several of the compositions of this invention were evaluated in vinylchloride suspension polymerizations. (described more fully later).

EXAMPLE I Phase Stabilities, Residue Impact Shock Sensitivities andSafety Test Results of Various 30% ACSP/Methylene Chloride/CosolventFormulations

These ACSP formulations were prepared by Procedure F in which methylenechloride was used as the low boiling water insoluble solvent. None ofthe formulations as made were sensitive to impact shock since theformulations contained 70% diluent and 30% peroxide. The residue impactshock sensitivity was determined in the following manner: At 25° C 5.0g. of the 30% ACSP/methylene chloride/cosolvent formulation was placedin a Petri dish (3.5 inches in diameter) and the formulation was exposedto the atmosphere for 4 hours at 25° C. The impact shock sensitivity ofthe residue was then determined. These results and phase stabilityresults at -20° C and -50° C after 17 weeks are shown in Example I TableA. If the formulation remained a liquid at the test temperature it wasgiven a "pass" grading whereas if solidification occurred it was given a"fail" grading. In the case of the residue impact shock sensitivity test"+" meant that the formulation residue was sensitive to shock whereas"-" meant that the formulation residue was not sensitive to shock.

The residue impact shock sensitivity test results show that a cosolventpossessing a boiling point of at least 165° C is required to produce aliquid acyl alkylsulfonyl peroxide formulation having acceptable residueimpact shock (not shock sensitive at 12 inches). In addition, theformulation should contain about 7% by weight of the solvent boilingabove 165° C. When no cosolvent was employed the residue was quite shocksensitive. The improved liquid ACSP formulations listed in Example ITable A were low viscosity liquids at -50° C whereas the commerical ACSPformulation, i.e., 28-30% ASCP/70-72% DMP, was a solid at -50° C.Although the commercial ACSP formulation passed the phase stability testat -20° C it solidified at slightly lower temperature (-23° C). Henceits storage phase stability at -20° C was borderline.

Example I Table B summarizes selected safety test results and thermalstability test results for 30% ACSP/56% methylene chloride/14% cosolventformulations in which the cosolvent was DMP, dibutyl phthalate (DBP),4-butyrolactone or Phosflex 500. Also included in Example I Table B areresults for the commercial liquid ACSP formulation (28-30% ACSP/70-72%ACSP) and 30% ACSP/70% methylene chloride (the control).

The safety test results show that the improved liquid acyl alkylsulfonylperoxide formulations, which contain 14% DMP, DBP, 4-butyrolactone andPhosflex 500, have improved safety when compared to the commercialliquid ACSP formulation.

The rapid heat temperatures were higher, maximum flame heights werelower and the ignition times (time required to ignite the formulation)were significantly longer. The thermal stabilities of these formulationsand the commercial liquid ACSP formulation at 0° C and -10° C were quitesimilar whereas these improved liquid acyl alkylsulfonyl peroxideformulations were more stable than was 30% ACSP/70% methylene chloride.

                                      EXAMPLE I                                   __________________________________________________________________________    TABLE A                                                                       30% ACSP/CH.sub.2 Cl.sub.2 /Cosolvent Formulations                            Phase Stabilities - Residue Impact Shock                                                           Phase Stabilities>17 Wks.                                                               Residue Impact Shock                           Cosolvent, %    B.P., ° C                                                                   -20° C                                                                      -50° C                                                                      1"                                                                              3"                                                                              6"                                                                              12"                                                                             24"                                                                             36"                                  __________________________________________________________________________    Toluene, 7.sup.1.                                                                             111  Pass Pass - + + + + +                                    Toluene, 14.sup.2.                                                                            111  Pass Pass - + + + + +                                    n-Butyl Acetate, 7.sup.1.                                                                     125  Pass Pass - + + + + +                                    n-Butyl Acetate, 14.sup.2.                                                                    125  Pass Fail - + + + + +                                    4-Butyrolactone, 7.sup.1.                                                                     204  Pass Pass - - - - + +                                    4-Butyrolactone, 14.sup.2.                                                                    204  Pass Pass - - - - - -                                    Butyl Lactate, 7.sup.1.                                                                       160-190                                                                            Pass Pass - + + + + +                                    Butyl Lactate, 14.sup.2.                                                                      160-190                                                                            Pass*                                                                              Pass*                                                                              - - - - - -                                    Ethyl Lactate, 7.sup.1.                                                                       154  Pass Pass - + + + + +                                    Ethyl Lactate, 14.sup.2.                                                                      154  Pass*                                                                              Pass*                                                                              + + + + + +                                    Triethyl Citrate, 7.sup.1.                                                                    294  Pass Pass + + + + + +                                    Triethyl Citrate, 14.sup.2.                                                                   294  Pass Pass*                                                                              - - - - - -                                    DMP, 14.sup.2.  283  Pass Pass*                                                                              - - - - - -                                    DBP, 14.sup.2.  192/10                                                                             Pass Pass*                                                                              - - - - - -                                    Phosflex 500, 14.sup.2.                                                                       >200 Pass Pass - - - - - -                                    Tricresyl Phosphate, 14.sup.2.                                                                265/10                                                                             Pass Pass - - - - - -                                    Texanol, 14.sup.2.                                                                            180/125                                                                            Pass Pass - - - - - -                                    Diisobutyl Ketone, 14.sup.2.                                                                  163-173                                                                            Pass Fail + + + + + +                                    Isobutyl Isobutyrate, 14.sup.2.                                                               144-151                                                                            Pass*                                                                              Fail + + + + + +                                    None (Control).sup.3.                                                                         --   Pass Pass - + + + + +                                    28-30% ACSP/70-72% DMP                                                                        --   Pass Fail - - - - - -                                    __________________________________________________________________________     *slight precipitate                                                           .sup.1. Formulation contained 30% ACSP/63% CH.sub.2 Cl.sub.2 /7% Cosolven      .sup.2. Formulation contained 30% ACSP/56% CH.sub.2 Cl.sub.2 /14%            Cosolvent                                                                      .sup.3. Formulation contained 30% ACSP/70% CH.sub.2 Cl.sub.2            

                                      EXAMPLE I                                   __________________________________________________________________________    TABLE B                                                                       Stability And Safety Tests - 30% ACSP/CH.sub.2 Cl.sub.2 /Cosolvent            Formulations                                                                                                   4-Butyro-.sup.3.                                                                    Phosflex.sup.3.                        COSOLVENT   DMP.sup.1.                                                                         None.sup.2.                                                                         DMP.sup.3.                                                                         DBP.sup.3.                                                                         Lactone                                                                             500                                    __________________________________________________________________________    % Cosolvent 70-72                                                                                --  14   14   14    14                                     Shock Sensitivity                                                                         Neg. 20"                                                                           Neg. 20"                                                                            Neg. 20"                                                                           Neg. 20"                                                                           Neg. 20"                                                                            Neg. 20"                               Rapid Heat, ° C                                                                    55   71    75   75   71    70                                     PVT No., mm.                                                                              <2.0 5.0   <2.0 <2.0 <2.0  <2.0                                   Burning Characteristics                                                       a) Ignition 4 secs.                                                                            140 secs.                                                                           70 secs.                                                                           70 secs.                                                                           65 secs.                                                                            60 secs.                               b) Active Burn.                                                                           1 sec.                                                                             Violent                                                                             3 secs.                                                                            1 sec.                                                                             3 secs.                                                                             3 secs.                                c) Other Burn.                                                                            120 secs.                                                                          puff after                                                                          5 secs.                                                                            5 secs.                                                                            5 secs.                                                                             5 secs.                                d) Max. Flame Ht.                                                                         4 ft.                                                                              ignition,                                                                           2 ft.                                                                              2 ft.                                                                              2 ft. 2 ft.                                                   self-exting-                                                                  uishing                                                      Thermal Stabilities                                                           % of Assay Loss,                                                              0° C/4 wks.                                                                        8.8    --  12.2 10.7 5.4   5.3                                    -10° C/4 wks.                                                                      0.0  6.6   0.7  0.0  0.0   0.0                                    __________________________________________________________________________     .sup.1. Formulation contained 28-30% ACSP/70-72% DMP.                         .sup.2. Formulation contained 30% ACSP/70% CH.sub.2 Cl.sub.2.                 .sup.3. Formulation contained 30% ACSP/56% CH.sub.2 Cl.sub.2 /14%             cosolvent.                                                               

EXAMPLE II Phase Stabilities, Residue Impact Shock Sensitivities andSafety Test Results of Various 35% and 40% ACSP/MethyleneChloride/Cosolvent Formulations

These ACSP formulations were prepared by the procedure described inExample I. None of the formulations as made were sensitive to impactshock and all were low viscosity liquids at -20° C. Phase stabilitiesafter 13 weeks at -20° C and -50° C and residue impact shocksensitivities are summarized in Example II Table A. In general, only theformulations with no high boiling solvent were sensitive to residueimpact shock. All of the improved liquid ACSP formulations passed the-20° C phase stability test whereas all failed the -50° C phasestability test. Hence they appear to have phase stabilities similar tothe commercial liquid ACSP formulation. However, since higher ACSPlevels (35% and 40%) are possible with the solvent systems employed theimproved liquid 35% and 40% ACSP formulations are superior to thecommercial liquid ACSP formulation. They also have lower viscositiesthan the commercial liquid ACSP formulation.

Example II Table B summarizes stability results and selected safetyresults for several improved liquid 35% ACSP/51% CH₂ Cl₂ /14% cosolventformulations. Example II Table C summarizes similar results for severalimproved liquid 40% ACSP/46% CH₂ Cl₂ /14% cosolvent formulations. Theseformulations have about the same stability as the commercial liquid ACSPformulation and have better safety results (rapid heat temperatures andmaximum flame heights) than the commercial liquid ACSP formulation.

                                      EXAMPLE II                                  __________________________________________________________________________    TABLE A                                                                       35% and 40% ACSP/CH.sub.2 Cl.sub.2 /Cosolvent Formulations                    Phase Stabilities - Residue Impact Shock                                                      ACSP                                                                              Phase Stabilities (13 wks.)                                                               Residue Impact Shock                          Cosolvent       %   -20° C                                                                       -50° C                                                                       3" 6" 12"                                                                              36"                                  __________________________________________________________________________    4-Butyrolactone, 14                                                                           35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    4-Butyrolactone, 14                                                                           40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    DBP, 14         35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    DBP, 14         40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    Triethyl Citrate, 14                                                                          35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    Triethyl Citrate, 14                                                                          40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    DMP, 14         35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    DMP, 14         40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    Butyl Lactate, 14                                                                             35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    Butyl Lactate, 14                                                                             40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    Dibutyl Maleate, 14                                                                           35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    Dibutyl Maleate, 14                                                                           40.sup.2.                                                                         Pass  Fail  -  -  -  +                                    Dioctyl Adipate, 14                                                                           35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    Dioctyl Adipate, 14                                                                           40.sup.2.                                                                         Pass  Fail  -  +  +  +                                    Phosflex 500, 14                                                                              35.sup.1.                                                                         Pass  Fail  -  -  -  -                                    Phosflex 500, 14                                                                              40.sup.2.                                                                         Pass  Fail  -  -  -  -                                    None (CH.sub.2 Cl.sub.2 only)                                                                 35.sup.1.                                                                         Pass  Borderline                                                                          +  +  +  +                                    None (CH.sub.2 Cl.sub.2 only)                                                                 40.sup.2.                                                                         Borderline                                                                          Fail  +  +  +  +                                    28-30% ACSP/70-72% DMP                                                                            Pass  Fail  -  -  -  -                                    __________________________________________________________________________     .sup.1. Formulation contained 35% ACSP/51% CH.sub.2 Cl.sub.2 /14%             cosolvent.                                                                    .sup.2. Formulation contained 40% ACSP/46% CH.sub.2 Cl.sub.2 /14%             cosolvent.                                                               

                  EXAMPLE II                                                      ______________________________________                                        TABLE B                                                                       Stability and Safety Tests - 35% ACSP/CH.sub.2 Cl.sub.2 /                     Cosolvent Formulations                                                                              4-Butyro-       Phosflex                                Cosolvent    DMP.sup.1.                                                                             lactone.sup.2.                                                                         DBP.sup.2.                                                                           500.sup.2.                              ______________________________________                                        % Cosolvent  70-72    14       14     14                                      Shock                                                                         Sensitivity  Neg. 20" Neg. 20" Neg. 20"                                                                             Neg. 20"                                Rapid Heat Temp.,                                                             ° C.  55       73       72     70                                      PVT No., mm. <2.0     <2.0     <2.0   <2.0                                    Burning Character                                                             a) Ignition   4 secs.  8 secs. 15 secs.                                                                             15 secs.                                b) Active Burn.                                                                             1 sec.   1 sec.   1 sec.                                                                               1 sec.                                 c) Other Burn.                                                                             120 sec. 24 secs. 24 secs.                                                                             23 secs.                                d) Max. Flame                                                                 Ht.           4 ft.    3 ft.    3 ft.  3 ft.                                  Thermal                                                                       Stabilities                                                                   % of Assay loss,                                                              0° C/4 wks.                                                                         8.8      7.5      14.0   9.4                                     -10° C/4 wks.                                                                       0.0      0.9      2.0    1.1                                     ______________________________________                                         .sup.1. Formulation contained 28-30% ACSP/70-72% DMP.                         .sup.2. Formulation contained 35% ACSP/51% CH.sub.2 Cl.sub.2 /14%             cosolvent.                                                               

                  EXAMPLE II                                                      ______________________________________                                        TABLE C                                                                       Stability And Safety Tests - 40% ACSP/CH.sub.2 Cl.sub.2 /                     Cosolvent Formulations                                                                              4-Butyro-       Phosflex                                Cosolvent    DMP.sup.1.                                                                             lactone.sup.2.                                                                         DBP.sup.2.                                                                           500.sup.2.                              ______________________________________                                        % Cosolvent  70-72    14       14     14                                      Shock Sensitivity                                                                          Neg. 20" Neg. 20" Neg. 20"                                                                             Neg. 20"                                Rapid Heat Temp.,                                                                          55       69       68     70                                      ° C                                                                    PVT No., mm. <2.0     <2<3     <2.0   <2<3                                    Burning Character                                                             a)Ignition   4 secs.  5 secs.  4 secs.                                                                              3 secs.                                 b)Active Burn.                                                                             1 sec.   1 sec.   1 sec. 1 sec.                                  c)Other Burn.                                                                              120 secs.                                                                              14 secs. 20 secs.                                                                             20 secs.                                d)Max. Flame 4 ft.    3 ft.    3 ft.  3 ft.                                   Ht.                                                                           Thermal                                                                       Stabilities                                                                   % of Assay Loss,                                                              0° C/4 wks.                                                                         8.8      6.3      13.2   9.1                                     -10° C/4 wks.                                                                       0.0      0.0      0.0    0.0                                     ______________________________________                                         .sup.1. Formulation contained 28-30% ACSP/70-72% DMP.                         .sup.2. Formulation contained 40% ACSP/46% CH.sub.2 Cl.sub.2 /14%             cosolvent.                                                               

EXAMPLE III Phase Stabilities of Various 30% /ACSP/55% DMP/15% CosolventFormulations

These improved liquid ACSP formulations were prepared by the methoddescribed in Procedure E. Example III Table A summarizes -20° C and -32°C phase stabilities of these improved liquid ACSP formulations after 10weeks. The results show that these improved liquid ACSP formulationshave superior phase stabilities at -32° C than the commercial liquidACSP formulation. The improved liquid ACSP formulations which werestored at -32° C for 10 weeks were then placed in a -45° C storage chestfor an additional 6 weeks. The phase stability results are summarized inExample III Table B. These results show that the 30% ACSP/55% DMP/15%cosolvent formulation in which the cosolvent was dimethylacetamide,4-butyrolactone or diethyl phthalate remained phase stable after anadditional 6 weeks at -45° C.

                  EXAMPLE III                                                     ______________________________________                                        TABLE A                                                                       Phase Stabilities of Various 30 % ACSP/55% DMP/                               15% Cosolvent Formulations                                                                  Phase Stabilities after 10 Weeks at                             Cosolvent (15%) -20° C                                                                              -32° C                                    ______________________________________                                        Diacetone alcohol                                                                             Pass         Pass                                             Tetrahydrofurfuryl alcohol                                                                    Pass         Pass                                             Ethyl acetoacetate                                                                            Pass         Pass                                             Tetramethylurea Pass         Pass                                             Hexamethylphosphoramide                                                                       Pass         Pass                                             Dimethylacetamide                                                                             Pass         Pass                                             N-Methyl-2-pyrrolidone                                                                        Pass         Pass                                             4-Butrolactone  Pass         Pass                                             Triethyl citrate                                                                              Pass         Pass                                             Butyl lactate   Pass         Pass                                             Dioctyl adipate Pass         Pass                                             Diethyl phthalate                                                                             Pass         Pass                                             DMP.sup.1.      Pass         Fail(solid)                                      ______________________________________                                         .sup.1. 28-30% ACSP/70-72% DMP (the commercial liquid ACSP formulation)  

                  EXAMPLE III                                                     ______________________________________                                        TABLE B                                                                       Phase Stabilities of Various 30% ACSP/55% DMP/                                15% Cosolvent Formulations                                                                  Phase Stabilities after 16 Weeks at                             Cosolvent (15%) -20° C                                                                             -32° C to -45° C                    ______________________________________                                        Diacetone alcohol                                                                             Pass        Fail                                              Tetrahydrofurfuryl alcohol                                                                    Pass        Fail                                              Ethyl acetoacetate                                                                            Pass        Fail                                              Tetramethylurea Pass        Fail                                              Hexamethylphosphoramide                                                                       Pass        Fail                                              Dimethylacetamide                                                                             Pass        Pass.sup.2.                                       N-Methyl-2-pyrrolidone                                                                        Pass        Fail                                              4-Butrolactone  Pass        Pass                                              Triethyl citrate                                                                              Pass        Fail                                              Butyl lactate   Pass        Fail                                              Dioctyl adipate Pass        Fail                                              Diethyl phthalate                                                                             Pass        Pass                                              DMP.sup.1.      Pass        Fail                                              ______________________________________                                         .sup.1. 28-30% ACSP/70-72% DMP (the commercial liquid ACSP formulation.       .sup.2. Very slight solids observed.                                     

EXAMPLE IV Phase Stabilities of 30% ACSP/35% DMP/35% DEP, 30% ACSP/70%4-Butyrolactone and 30% ACSP/52.5% DMP/17.5% 4-ButyrolactoneFormulations

These improved liquid ACSP formulations were prepared by the methoddescribed in Procedure E. Also prepared by this method were 30% ACSP/70%DBP and 30% ACSP/70% DEP. Phase stabilities were determined on theseACSP formulations at -50° C after 9 weeks. The results are summarized inExample IV Table. These results show that

                  EXAMPLE IV                                                      ______________________________________                                        -50° C Phase Stabilities of Various                                    Liquid 30% ACSP Formulations                                                                           Phase Stabilities after                              Solvent, %                                                                              Cosolvent, %   9 weeks at -50° C                             ______________________________________                                        DMP, 70.sup.1                                                                           None           Fail (solid)                                         DBP, 70   None           Fail (solid).sup.2                                   DEP, 70   None           Fail (solid)                                         4-Butyro-                                                                     lactone, 70                                                                             None           Pass (slightly viscous                                                        liquid)                                              DMP, 35   DEP, 35        Pass (glass-like liquid)                                       4-Butyro-                                                           DMP, 52.5 lactone, 17.5  Pass (liquid)                                        ______________________________________                                         .sup.1. Similar to the commercial liquid ACSP formulation.                    .sup.2. Failed after 4 weeks at -18° C                            

4-butyrolactone is a very good solvent for ACSP when used alone or incombination with DMP. In addition use of DMP or DEP alone results insolid formation at -50° C (with DBP solidification occurred at -18° C)whereas use of a 1/1 mixture of DMP and DEP produced a phase stable 30%ACSP solution at -50° C. The latter result was not expected since onewould not normally expect the solubility of ACSP in a mixture ofsolvents to be better than the solubility of ACSP in either solventalone (in this case the -50° C phase stability is a qualitative measureof the ACSP solubility in the solvents or solvent systems employed).

EXAMPLE V Phase Stabilities of Various 30%, 35%, 40% and 45%ACSP/DMP/DEP Liquid Formulations

These improved liquid ACSP formulations were prepared by the methodoutlined in Procedure B starting with wetted solid ACSP. The solventmixtures obtained in the final ACSP formulations were those employedduring work-up. Phase stabilities at -20° C and -45° C after 20 weeksare summarized in Example V Table. The results showed that mixed solventsystems composed of DMP and DEP produced ACSP liquid formulations thatwere phase stable at -45° C and had ACSP concentrations of greater than40% whereas the commercial liquid ACSP formulation (28-30% ACSP/70-72%DMP) and 30% ACSP/70% DEP solidified at -45° C. The results also showthat a wide range of DMP/DEP solvent compositions give phase stableliquid ACSP formulations at -45° C.

                  EXAMPLE V                                                       ______________________________________                                        30%, 35%, 40% and 45% ACSP/DMP/DEP                                            Formations                                                                                    Phase Stabilities after 20 wks.                               ACSP,%  DMP, %   DEP, %   -20° C                                                                           -45° C                             ______________________________________                                         1.     70        0       Pass      Fail                                      30      62        8       Pass      Fail                                      30      55       15       Pass      Pass                                      30      45       25       Pass       Pass.sup.2.                              30      35       35       Pass      Pass                                      30      25       45       Pass      Pass                                      30      15       55       Pass      Fail                                      30       0       70       Fail      Fail                                      35      51       14       Pass      Pass                                      40      47       13       Pass      Pass                                      45      43       12       Pass       Pass.sup.2.                              ______________________________________                                         .sup.1. Similar to the commercial liquid ACSP formulation.                    .sup.2. Slight solids - borderline phase stability.                      

EXAMPLE VI Phase Stabilities of Various Liquid ACSP Formulations at -23°C (-10° F)

Half-gallon samples of 30% ACSP/55% DMP/15% 4-butyrolactone and 30%ACSP/55% DMP/15% DEP were prepared by the method described in ProcedureB. These improved liquid ACSP formulations and a gallon sample of thecommercial liquid ACSP formulation (28-30% ACSP/70-72% DMP) were phasestability tested at -23° C (-10° F) for 16 weeks. Both improved liquidACSP formulations remained liquid at -23° C (-10° F) over the testperiod whereas the commercial liquid ACSP formulation solidified aftertwo weeks at -23° C (-10° F).

EXAMPLE VII Phase Stabilities of Miscellaneous Improved Liquid ACSPFormulations at -10° C and -25° C

20%, 30%, 40% and 44% ACSP formulations in a 1/1 solvent mixture of DMPand acetone were prepared from wetted solid ACSP (60-65%) usingProcedure B-1. Other formulations which were prepared by this procedurewere 30% ACSP/35% DMP/35% ethyl acetate and 35% ACSP/32.5% DMP/32.5% CH₂Cl₂. Phase stability results at -10° C and -25° C after 4 weeks aresummarized in Example VII Table. The results showed that all of theabove improved liquid ACSP formulations had better phase stabilities at-25° C than the commercial liquid ACSP formulation.

                  EXAMPLE VII                                                     ______________________________________                                        Phase Stabilities of Miscellaneous                                            Improved ACSP Formulations                                                    ACSP   DMP     Cosol-     Phase Stabilities after 4 wks. at                   %      %       vent, %    -10° C                                                                           -25° C                             ______________________________________                                        20     40      acetone, 40                                                                              Not done  Pass                                      30     35      acetone, 35                                                                              Pass      Pass                                      40     30      acetone, 30                                                                              Not done  Pass                                      44     28      acetone, 28                                                                              Pass      Pass                                      30     35      ethyl acetate,                                                                           Pass      Pass                                                     35                                                             35     32.5    CH.sub.2 Cl.sub.2, 32.5                                                                  Pass      Pass                                      28-30.sup.1.                                                                         70-72   None       Pass      Fail.sup.2.                               ______________________________________                                         .sup.1. Corresponds to the commercial liquid ACSP formulation.                .sup.2. Solid after two weeks at -23° C (see Example VI).         

EXAMPLE VIII Processes for Preparing 30% ACSP/55% DMP/15%4-Butyrolactone

The objective of this example was to determine the best method forpreparation of 30% ACSP/55% DMP/15% 4-butyrolactone. The first sample(1) was prepared by dissolving washed, wetted solid ACSP with a 55/15mixture of DMP and 4-butyrolactone followed by MgSO₄ drying. The secondsample (2) was prepared by Procedure C whereas the third sample (3) wasprepared by Procedure D. The three samples of 30% ACSP/55% DMP/15%4-butyrolactone were then stored at -45° C for 4 days. The appearance ofthe samples at -45° C was then recorded. The results are summarizedbelow and show that Procedure

    ______________________________________                                        30% ACSP/55% DMP/15% 4-Butyrollactone Samples                                            Preparative Appearance after 4 days                                Sample     Procedure   at-45° C                                        ______________________________________                                        (1)        B-1         Cloudy-water crystals                                  (2)        C           Clear liquid                                           (3)        D           Clear liquid                                           ______________________________________                                    

C and D were the best preparative methods when 4-butyrolactone wasemployed as a cosolvent in these improved ACSP formulations. Apparantly4-butyrolactone has a great affinity for water.

EXAMPLE IX Phase Stabilities of Improved Liquid 30% Acetylt-Amyl-Sulfonyl Peroxide (ATASP)/DMP/Cosolvent Formulations.

30% ATASP/70% DMP (a prior art composition) and 30% ATASP/35% DMP/35%DEP were prepared by Procedure B whereas 30% ATASP/55% DMP/15%4-butyrolactone was prepared by Procedure D. Phase stability results at-20° C and -32° C after 15 weeks are summarized in Example IX Table andshow that the improved liquid 30% ATASP formulations have phasestabilities at -32° C which are superior to those of the prior artcomposition (30% ATASP/70% DMP).

                  EXAMPLE IX                                                      ______________________________________                                        Phase Stabilities of Improved                                                 Liquid 30% ATASP Formulations                                                                              Phase Stabilities                                ATASP,   DMP,     Cosol-     after 15 wks. at                                 %        %        vent, %    -20 ° C                                                                         -32° C                           ______________________________________                                        30.sup.1.                                                                              70       None       Pass     Fail                                                                          (solid)                                 30       35       DEP, 35    Pass     Pass                                    30       55       4-Butyro-  Pass     Pass                                                      lactone, 15                                                 ______________________________________                                         .sup.1 Prior art composition.                                            

EXAMPLE X 50° C/8 Hours Vinyl Chloride Suspension PolymerizationEfficiencies of Improved Liquid ACSP Formulations

Several of the improved liquid ACSP formulations described in theExamples above and the commercial liquid ACSP composition (28-30%ACSP/70-72% DMP) were evaluated in vinyl chloride suspensionpolymerizations at 50° C/8 hours. The following recipe was employed inthese polymerizations:

    ______________________________________                                        Ingredient               Parts by Weight                                      ______________________________________                                        Vinyl chloride monomer   100                                                  Water (triple distilled) 175                                                  Methocel* (65 HG, 50 cps) (1% aqueous soln.)                                                           60                                                   Aerosol MA** (1% aqueous soln.)                                                                        15                                                   Free-radical initiator   variable                                             ______________________________________                                         *Methylcellulose (Dow Chemical Co.)                                           **Sodium salt of dihexyl sulfosuccinate (American Cyanamid Co.)          

PROCEDURE

Pop bottles were employed. Water, aqueous Methocel and aqueous AerosolMA were added to each bottle and the contents were frozen at -20° C. ThepH of this system was 6.0 to 6.5 at room temperature. It is conceivablethat the pH could be varied by the use of buffers so as to maximize oroptimize the efficiency of the polymerization. Other suspending agentsand/or surfactants (anionic, cationic, nonionic and amphoteric) can beused in place of this suspension system in order to insure that asuspension is maintained throughout the polymerization. To the bottleswere then added varying amounts of free-radical initiators (severalbottles for each initiator) and the required amount of liquid vinylchloride monomer (at -14° C). The bottles were crown-capped, enclosed insafety cages and placed in a constant temperature bottle polymerizermaintained at 50° C. End-over-end tumbling at a rate of 25 revolutionsper minute was employed for agitation and the polymerizations wereallowed to proceed for 8 hours. At the end of that time the bottles wereremoved from the bottle polymerizer, cooled to 0° C and vented of vinylchloride monomer. Venting of unreacted vinyl chloride monomer seldomtook more than 15 to 30 minutes; hence, postpolymerization wasinsignificant. The amount of polymer produced was determinedgravimetrically (by difference in weight) and plots of initiatorrequired versus % conversion were constructed for each initiator and theamounts of initiators (in grams and in moles) required at 90% conversionwere determined from the plots. These results are shown in Example XTable. The results show that the improved liquid ACSP formulations hadvinyl chloride polymerization efficiencies similar to those of thecommerical liquid ACSP formulation. Apparently the solvents employed hadlittle or no effect on polymerization efficiency. The improved liquidACSP formulations of this invention were more advantageously employed invinyl chloride polymerizations than was the commercial liquid ACSPcomposition owing to their improved handling and storage characteristics(phase stabilities). PVC producers consider the handling and storagecharacteristics to be important properties of the initiators that theyemploy.

    ______________________________________                                        EXAMPLE X                                                                     50° C/8 Vinyl Chloride                                                 Suspension Polymerization Efficiencies                                                         (Cosol-     Pure ACSP                                                         vent)       Required/100g                                          Sol-       Second      VC1 at 90%                                       ACSP, vent,      Sol-        Conversion                                       %     %          vent, %     Grams  Moles × 10.sup.4                    ______________________________________                                                                     0.0274-                                          28-30.sup.1.                                                                        DMP, 70-72 None        0.0322 1.23-1.45                                 30    CH.sub.2 Cl.sub.2, 56                                                                    DMP, 14     0.029  1.31                                      30    CH.sub.2 Cl.sub.2, 35                                                                    DMP, 35     0.025  1.12                                      30    CH.sub.2 Cl.sub.2, 56                                                                    DBP, 14     0.0258 1.16                                      30    CH.sub.2 Cl.sub.2, 56                                                                    4-Butyro-   0.0250 1.13                                                       lactone, 14                                                  30    CH.sub.2 Cl.sub.2, 56                                                                    Phosflex    0.0255 1.15                                                       500.sup.2. , 14                                              30    DMP, 55    DEP, 15     0.033  1.49                                      30    DMP, 35    Acetone, 35 0.0233 1.05                                      30    DMP, 35    Ethyl Acetate,                                                                            0.0266 1.20                                                       35                                                           ______________________________________                                         .sup.1. The commercial liquid ACSP composition.                               .sup.2. A chlorinated triaralkyl phosphate manufactured by the Stauffer       Chemical Company.                                                        

EXAMPLE XI Phase Stabilities of 30% and 40% ACSP Liquid Formulationsusing Propylene Carbonate as a Solvent

Samples of 30% ACSP/70% propylene carbonate, 40% ACSP/60% propylenecarbonate, 30% ACSP/35% propylene carbonate/35% DMP, 30% ACSP/35%propylene carbonate/35% ethyl acetate and 30% ACSP/70% ethyl acetatewere prepared by procedure E. The phase stabilities of theseformulations at -20° C and -45° C were determined and the results aresummarized in Example XI Table. The results show that propylenecarbonate alone or in combination with DMP or ethyl acetate is anexcellent solvent for ACSP.

                                      Example XI Table                            __________________________________________________________________________    Liquid 30% and 40% ACSP Formulations                                                                       Phase Stabilities                                ACSP. %                                                                             Solvent, %   Cosolvent, %                                                                            Days at -20° C                                                                  Days at -45° C                   __________________________________________________________________________    30    Propylene carbonate, 70                                                                    --        8 Pass   8 Pass                                  40    Propylene carbonate, 60                                                                    --        8 Pass   8 Pass                                  30    Propylene carbonate, 35                                                                    Ethyl acetate, 35                                                                       8 Pass   8 Pass                                  30    Ethyl acetate, 70                                                                          --        8 Pass   4 Fail*                                 __________________________________________________________________________     *Solid formation                                                         

EXAMPLE XII Phase Stabilities of 30% Liquid ACSP Formulations Preparedwith Trisolvent Systems

Samples of 30% ACSP/23.3% DMP/23.3% DEP/23.3% ethyl methyl phthalate(EMP) and 30% ACSP/20% 4-butyrolactone/25% DMP/25% DEP were prepared byprocedure E. The 1/1/1 DMP/DEP/EMP solvent system used to produce theformer formulation was prepared in the following manner:

A mixture of 1.0 mole of phthalic anhydride, 3.0 moles of ethanol, 3.0moles of methanol and 3.0 g of 98% H₂ SO₄ was refluxed at 74° C for 10hours. After working-up by procedures well known in the art a liquidproduct was obtained which had a composition weight ratio of 22/3/22 forDMP/DEP/EMP according to gas chromatographic analysis. To 50 g of thisproduct was added 20.2 g of DEP. This produced the desired 1/1/1 mixtureof DMP/DEP/EMP.

the two 30% liquid ACSP formulations were then phase stability tested at-20° C and -45° C for 4 days and were found to be phase stable (remainedliquid) at both temperatures.

EXAMPLE XIII Complete Solidification Temperatures of Solvents andSolvent Mixtures

The complete solidification temperatures (C.S.T.) of various solventsand solvent mixtures were determined. In the case of pure solvents theC.S.T. corresponded to the melting point temperature of the pure solventas determined in the usual manner. In the case of solvent mixtures theC.S.T. corresponded to the temperature below which a liquid phase wasabsent and above which a liquid phase was present. The C.S.T. of asolvent mixture was determined by adding about 40 g of solvent mixtureto a two ounce clear glass bottle, cooling the sample in a -30° C to-35° C bath and scratching the inside of the bottle with a glassthermometer until complete solidification occurred or until the solventmixture remained liquid or retained a liquid phase after about one hourat approximately the bath temperature. In the latter case the C.S.T. wasconsidered to be below the temperature ultimately attained by thesolvent mixture. In the former case the C.S.T. was taken as thetemperature at which complete solidification occurred.

Example XIII Table summarizes the complete solidification temperatures(C.S.T.) for various solvents and solvent systems which were employedfor the preparation of various acyl alkylsulfonyl peroxide formulationsderived from solid acyl alkylsulfonyl peroxides. Example XIII Table alsostates whether or not the solvent or solvent system was used in theimproved liquid acyl alkylsulfonyl peroxide formulations of thisinvention. The results of this example and those of previous examplesshow that solvent or solvent systems which have complete solidificationtemperatures (C.S.T.) above about -10° C fail to produce attractiveliquid formulations whereas those solvents or solvent mixtures withC.S.T. temperatures below about -10° C produce attractive improvedliquid acyl alkylsulfonyl peroxide formulations which are derived fromsolid acyl alkylsulfonyl peroxides.

                  Example XIII Table                                              ______________________________________                                        Complete Solidification Temperatures of Solvents                              and Solvent Mixtures                                                                                          Solvent or                                                                    Solvent System                                Solvent                 C.S.T., for Invention                                 Parts   Cosolvent, Parts                                                                              ° C                                                                            Compositions                                  ______________________________________                                        DMP, 70  --             ca. 2   No                                            DEP, 70  --             ca. 0   No                                            DMP, 62 DEP, 8          -7      No                                            DMP, 55 DEP, 15         <-28    Yes                                           DMP, 45 DEP, 25         <-28    Yes                                           DMP, 35 DEP, 35         <-28    Yes                                           DMP, 55 4-Butyrolactone, 15                                                                           <-28    Yes                                           DMP, 35 Ethyl acetate, 35                                                                             <-28    Yes                                           CH.sub.2 Cl.sub.2, 56                                                                 DMP, 14         <-28    Yes                                           CH.sub.2 Cl.sub.2, 56                                                                 4-Butyrolactone,14                                                                            <-28    Yes                                           DMP, 35 Propylene carbonate, 35                                                                       <-28    Yes                                           ______________________________________                                    

What is claimed is:
 1. In a method of polymerizing a vinyl monomer inthe presence of an initiator, the improvement comprising using in aninitiating amount in the temperature range of 0° C. to 80° C. a liquidsolution composition which is a storable stable liquid at 0° to -40° C.consisting essentially ofa. 10 to 70% by weight of a solid acylalkylsulfonyl peroxide with a melting point between -10° and 70° C.having the formula ##STR3## where (1) R₁ is an alkyl of 1 to 4 carbonsand(2) R₂ is selected from the group consisting of an alkyl ormonochloroalkyl radical of 3 to 18 carbons and a cycloalkyl orcyclomonochloroalkyl radical of 4 to 12 carbons, and b. 90 to 30% byweight of a polar or polarizable solvent or solvent system having acomplete solidification temperature below about -10° C and a miscibilitynumber of greater than 8 and less than 21, which solvent or solventsystem possesses at least about 20% by weight based on the solid acylsulfonyl peroxide of a solvent which has a boiling point of at least165° C at 760 torr.
 2. In the method of claim 1 wherein the vinylmonomer is vinyl chloride.
 3. In the method of claim 2 wherein thecomposition of the initiator consists essentially of in percent byweight of compositiona. 30% of acetyl cyclohexylsulfonyl peroxide, b.55% of dimethyl phthalate, and c. 15% of diethyl phthalate.
 4. In themethod of claim 2 wherein the composition of the initiator consistsessentially of in percent by weight of compositiona. 30% of acetylcyclohexylsulfonyl peroxide, b. 56% methylene chloride, and c. 14% ofdimethyl phthalate.
 5. In the method of claim 2 wherein the compositionof the initiator consists essentially of in percent by weight ofcompositiona. 30% of acetyl cyclohexylsulfonyl peroxide, b. 56% ofmethylene chloride, and c. 14% of 4-butyrolactone.
 6. In the method ofclaim 2 wherein the composition of the initiator consists essentially ofin percent by weight of compositiona. 30% acetyl cyclohexylsulfonylperoxide, b. 35% of dimethyl phthalate, and c. 35% of ethyl acetate. 7.In the method of claim 1 wherein the composition of the initiatorconsists essentially of in percent by weight of compositiona. 30% ofacetyl t-amylsulfonyl peroxide, b. 35% of dimethyl phthalate, and c. 35%of diethyl phthalate.
 8. In the method of claim 1 wherein thecomposition of the initiator consists essentially of in percent byweight of compositiona. 30% of acetyl cyclohexylsulfonyl peroxide, andb. 70% of 4-butyrolactone.
 9. In the method of claim 1 wherein thecomposition of the initiator consists essentially of in percent byweight of compositiona. 35% of acetyl cyclohexylsulfonyl peroxide, b.51% of dimethyl phthalate, and c. 14% of diethyl phthalate.
 10. In themethod of claim 1 wherein the composition of the initiator consistsessentially of in percent by weight of compositiona. 40% of acetylcyclohexylsulfonyl peroxide, b. 47% of dimethyl phthalate, and c. 13% ofdiethyl phthalate.
 11. In the method of claim 1 wherein the compositionof the initiator consists essentially of in percent by weight ofcompositiona. 30% of acetyl cyclohexylsulfonyl peroxide, b. 35% ofpropylene carbonate, and c. 35% of ethyl acetate.
 12. In the method ofclaim 1 wherein the composition of the initiator consists essentially ofin percent by weight of compositiona. 30% of acetyl cyclohexylsulfonylperoxide, b. 35% of propylene carbonate, and c. 35% of dimethylphthalate.